The present invention relates to a sample transfer device for a transmission electron microscope, a scanning transmission electron microscope and the like and more particularly, to a sample transfer device which can insert a sample into the transmission electron microscope or scanning transmission electron microscope while suppressing to a minimum the time to expose the sample to the atmospheric environment.
With processing critical dimensions of a semiconductor device, a magnetic device and the like reduced minutely and with high integration advanced, degradation in device characteristics and decrease in reliability have been bringing about more important problems than before. In recent years, in order to analyze defects of semiconductor device in a nanometer region and ascertain causes of defects thoroughly to solve them in the course of development of new processes and mass-production, spectral analysis and two-dimensional element distribution analysis using (scanning) transmission electron microscopy ((S) TEM) and electron energy loss spectroscopy (EELS) have become indispensable analysis means.
Further, in connection with an energy environmental material such as a material of a positive pole of Li battery, improvements in material characteristics have been desired to make more rapid progress than before. For the purpose of improving the material characteristics, controlling of structures and chemical bond status at nano-level holds important key. Therefore, needs for the aforementioned analytical technologies have been increasing.
Conventionally, a sample or specimen for transmission electron microscopy or scanning transmission microscopy is fixed to a sample stage for transmission electron microscope called a sample mesh. The manner of fixing the sample differs depending on the shape of the sample and the observing field of the sample. For example, in the case of particles of nanometer size, the particles are scattered directly to the sample stage in a sample preparation chamber such as a globe box, for instance, filled with argon gas. Further, when a portion determined faulty in electrical characteristics or the like in a semiconductor device or magnetic device is desired to be observed, a region inclusive of an observing objective and its neighborhood is extracted by means of a focused ion beam (FIB) apparatus and is fixed to the sample stage by using tungsten gas.
Then, after the sample to be observed in the transmission electron microscope has been fixed to the sample stage, the sample stage is mounted on a sample holder for transmission electron microscope and in general, the sample holder per se mounting the sample stage is transferred in atmospheric environment and is then inserted into the transmission electron microscope. The sample holder is mainly classified into a top-end type sample holder and a side-entry type sample holder but in recent years, the side-entry type sample holder is the prevalent mainly.
In the above case, the sample holder is transferred in atmospheric environment from a sample preparation room or the focused ion beam apparatus to the transmission electron microscope. Accordingly, when a sample to be measured is easy to react with water content or oxygen, there is a possibility that the sample will be changed in quality or its oxidization will proceed, thus making desired observation and element analysis difficult. Conventionally, techniques have been disclosed in which a measurement sample of an electron microscope as typified by the transmission electron microscope is inserted into the electron microscope while suppressing to a minimum the time to expose the sample to the atmospheric environment.
More particularly, one may refer to the following documents:    PATENT DOCUMENT 1: JP-A-60-264033    PATENT DOCUMENT 2: JP-A-2009-80005    PATENT DOCUMENT 3: JP-A-63-287032    NON-PATENT DOCUMENT 1: Japanese Journal of Applied Physics Vol. 46, pages L1141 to L1142
Patent Document 1 discloses an ambience sample chamber detachably attached to a sample inclining unit for electron microscope so that a side-entry type sample holder may be mountable/dismountable into/from the ambience sample chamber and also discloses a member for supporting the sample holder for use in the ambience sample chamber for electron microscope, which support member facilitates taking-in and out operation of the sample holder to the sample inclining unit.
Non-patent Document 1 discloses a technique according to which a side-entry type sample holder mountable to the transmission electron microscope sample stage is provided with, at its tip end, an O-ring and a sleeve and when transferring the side-entry type sample holder in the atmospheric environment, a neighborhood of the sample stage is covered with the sleeve, the sample stage having its neighborhood kept to be covered with the tip end sleeve is inserted into the transmission electron microscope and after completion of insertion, the tip end sleeve is uncovered to permit the sample fixed to the sample stage to be observed.
Patent Document 2 discloses a sample conserving device according to which when preparing a sectioned sample by using a focused ion beam apparatus, in order to suppress to a minimum the time to expose the sample to the atmospheric environment, a main case having a vacuum evacuative space in communication with a vacuum evacuation unit decompressed by a vacuum decompression unit and a mountable/dismountable case having an inner space for having the custody of the sample are provided, so that the sample subject to sectioning can be transferred while conserving the sample in vacuum ambience with ease.
Further, Patent Document 3 discloses a technique concerning a sample transfer container composed of an airtight chamber for accommodating a sample stage, a gate valve provided in communication with the airtight chamber and means for making the position of the sample stage moveable in three-dimensional direction, so that the sample stage can be transferred in vacuum condition between a unit for cutting wiring on a sample and a unit for connecting the wiring.
As will be seen from the foregoing, in any of the disclosed techniques, the sample can be inserted into the electron microscope or the sample preparation apparatus while suppressing to a minimum the time to expose the sample to the atmospheric environment.